Hydrogen absorption properties of uranium-zirconium alloys

Hydrogen absorption-desorption properties of the UZr0.29 alloy and uranium metal were investigated in detail at hydrogen pressures as high as to 0.4 MPa and over the temperature range of 300-873 K. Both UZr0.29 alloy and uranium metal showed similar hydrogen isotopic effect and hysteresis effect. UZr0.29 alloy absorbed hydrogen (deuterium) up to 2.3H (2.18D) atoms per F.U. (formula unit) by only one-step reaction and hence each desorption isotherm had a single plateau over nearly the whole hydrogen composition range. While for those with large amount of zirconium, such as U2Zr and UZr2.3, more stable hydrides than UH3 were formed, which brought some additional plateaus to the desorption isotherms. Uranium-zirconium alloys had a little lower dissociation pressure than that of pure uranium; and the larger the amount of zirconium added to the alloys, the lower the dissociation pressure. However, the uranium-zirconium alloys showed high durability against powdering upon hydrogenation and may have good heat conductivity.